Scenariobased design

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Scenario-based design

• Chris Fowler
• Chimera Institute of Social and Technical Change
• University of Essex

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Contents

• Context
• Defining a scenario
• Scenarios for Need Analysis
• Scenarios for Usability Engineering
• .and the e-framework?
• Issues Conclusions

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Context

• Military
• Planning Decision-making
• User Needs Analysis
• Usability Engineering
• Others (inc. Learning Design)

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Defining a Scenario

• Narrative (a story)
• Bounded (or scoped)
• Descriptive
• Actors
• Activities (tasks)
• Things (objects)
• Within a given time-frame
• For a given purpose
• Communication (shared)
• Analysis/design
• Decision-making

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Defining a Scenario (cont)

• They can describe
• current/now or as is
• and/or
• proposed/future or what-if situations.
• Current is more about problem analysis
• Proposed is more about building a paper-based
  prototype or representation

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Focus

• Military
• Planning Decision-making
• User Needs Analysis
• Usability Engineering
• Others (inc. Learning Design)

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User Needs Analysis
The core of any design scenario is a narrative
around a user, trying to achieve a task goal
involving a thing within a given context or
environment (e.g. the workplace).
User
User
Object
Task Goal
Task Goal
Object
Context
Context
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Scenarios DesignHierarchical Task Analysis
(HTA)
High Level Design
Scenarios
T1 Task Goal
T2.1
T2.2
T3.2.1.1
T3.2.1.2
T3.2.2.2
T3.2.2.1
T4.3.2.1.1.1
Low Level Design
Use Cases
HCI boundary
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SUNA An Overview
CF1
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SUNA Scenario

• Over the next term she uses the case study to
  inform her own teaching, and from her experience
  of using it, she annotates it with her own notes
  ltneed to annotategt, and saves the annotated
  version and thus growing the context. Indeed,
  she came to the stage of being so critical of the
  Case Study that she changed it by adding some of
  her own material ltneed to editgt. Eventually she
  decided it would be easier to create a new one
  ltneed to creategt and submit it. Later on, she
  notices that the University QA officer had
  deleted the original Case Study ltneed to deletegt,
  and hers was now offered as the best example of
  effective practice in that area.

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User Needs Table
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User Needs Hierarchy
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Mapping Technology onto Needs
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Creating Use Cases

• A Use Case is defined as
• a concrete description of activity that the user
  engages in when performing a specific task,
  description sufficiently detailed so that design
  implications can be inferred and reasoned about
  (Carroll 1995).
• It starts with a functional need (e.g.
  Withdraw cash from the ATM) but describes the
  how (place card in slot type in PIN select
  service)

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Rossons Carrolls (2002) Scenario-based
Usability Engineering
A strong emphasis on usability
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Problem Scenarios

• Descriptions of the current situation
• Used to identify claims and trade-offs that
  may impact usability
• A problem claim is about the positive and
  negative effects of features on the actors
  experience
• E.g. Situation Feature Students can email their
  tutors
• Pos. offers timely and effective support
• Neg. takes up too much of the teachers time
• Trade-off Teachers will only respond to emails
  about specific assignments (a need?)

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Activity Scenarios

• Transform current activities to use new design
  ideas (proposed scenario) or new functionality
• Inputs
• Problem claims/trade-offs (keep the best
  features!)
• New technologies, metaphors or design ideas
  (from brainstorming)
• HCI knowledge
• Current practice knowledge
• Output
• Design Claims (new design features their
  implications (SUNA Needs?)

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Information Scenarios

• Making sense of how users perceive, interpret and
  make sense of information
• Elaborate activities so that they include
  perceptual presentation details.

Activity Design Scenario When Delia shows Alicia
an email invitation to the VSF, the two of them
decide to follow the link right then
Information Design Scenario The email includes a
string that Delia recognises as a URL in.

• Would a template (e.g. object name
  representation required action flow.) rather
  than a Scenario be a more effective
  representation?

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Interaction scenarios

• These are about physical actions and system
  responses that enact and respond to the users
  task goals and needs.
• A use case?

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SUNA vs Scenario-based Usability Engineering

• SUNA has no problem scenarios such information
  is owned shared by experts
• SUNAs Scenarios SBUEs Activity Scenarios are
  similar
• Many of SUNAs scenarios also cover Information
  and Interaction scenarios

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The e-framework?

• Requires all the pieces to fit together as
  seamlessly and effortlessly as possible,
  including, for example
• Open Standards
• Common terms/definitions
• Agreed framework/process
• Open APIs or source code
• Or a common design/development/deployment
  approach UIDM? Agile? UML? RAD? ANT? MAVEN?

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User Innovation Development Model
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Facilitation of the UIDM
Generating ideas, opportunities, propositions
Requirements Validation
High Level Design representations
Testing
Underpinning features
Understanding User/Business Needs Contexts
of use
Rapid analysis prioritisation of ideas
Buy or build decisions
Deploying
Building
Stage 1
Stage 2
Stage 3
User engagement
Transition decision
Technical Development
Examples of activities
Information gathering Scenario building Stakeholde
r analysis
Value Attribution Maturity Models
Scenario analysis Business modelling
UML
Training Support
Code testing Component testing System
testing Field trials
Brainstorming Mind Mapping
Scenario validation
Use cases Story boards
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Issue 1 Where do scenarios come from?

• Information gathered templates, marketing
  docs previous products
• An Individual (beware of design bullies!!!)
• Expert group (SUNA - proposed only scenario or
  USTM now proposed descriptions
• Combinations of the above

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Issue 2 One Scenario or Many?

• SUNA can generate a number of scenarios but all
  at the same level no concept of a super
  scenario.
• SBUE creates many scenarios at many levels too
  many? Perhaps only problem and activity
  scenarios are true scenarios.

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Issue 3 Non-functional Needs?

• Needs are what people want the system to do.
• Tasks functional needs
• Many Non-functional needs e.g.
• training
• usability
• acceptability (organisational/social issues)
• Cannot be derived from a HTA nor from SUNA
  approach

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Non-functional needs?

• These are about change so you need a baseline
  (a current description or scenario).
• So SBUE is better (problem compared to activity
  scenarios).

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USTM Approach to Change
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Issue 4 How valid are Scenarios?

• To be valid, they should be
• Grounded (based on good, valid and trusted back
  ground information)
• Realistic (evaluate them with users)
• Consistent (same conditions should generate
  similar scenarios)
• Coherent and complete
• Useful (interface with existing design methods)
• Economical (in time and money)

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Conclusions

• Need for clearer definitions
• Need to know how many
• Need to combine SUNA,
• SBUE and USTM to create
• a more complete approach (inc non-functional
  needs technical manuals)
• Must be linked into existing
• design methods
• Art, Craft or Science?

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Useful readings

• Fowler, C.J.H, van Helvert, J Gardner, M.G, and
  Scott, J.R. (in press). The use of scenarios in
  designing and delivering learning systems. In H.
  Beetham R. Sharpe, Rethinking Pedagogy in a
  Digital Age Designing and delivering e-learning.
  London Routledge.
• Van Helvert, J. and Fowler, C. (2004) Scenarios
  for Innovation (SUNA), in Alexander and N.
  Maiden (eds.) Scenarios and Use Cases Stories
  through the System Life-Cycle. London Wiley.
• Rosson, M.B. and Carroll, J.M. (2002) Usability
  Engineering Scenario-based Development of
  Human-Computer Interaction. London Academic
  Press.
• Carroll, J.M (1995) Introduction The Scenario
  Perspective on System Development. In J.M.
  Carroll (ed.) Scenario-Based Design Envisioning
  work and Technology in System Development New
  York Wiley
• Hutt, A.T.H., Donnelly, N., Macaulay, L.A.,
  Fowler, C.J.H., Twigger, D. (1988) Describing a
  product opportunity A method for understanding
  the users' environment. In D. Diaper R. Winder
  (eds). People Computers III. Cambridge CUP.

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Thank you

• cfowler_at_essex.ac.uk